1. Field of the Invention
This invention relates to novel penicillin compounds and pharmaceutically acceptable salts thereof, and to a process for preparing such compounds and salts. More particularly, this invention relates to penicillin compounds of the following formula (I), or pharmaceutically acceptable salts thereof, and to processes for preparing such compounds or salts.
2. Description of the Prior Art
Penicillin type compounds have antibacterial activities and many derivatives thereof have been produced hitherto.
Recently, a research on penicillin compounds aims to develop a useful compound against Gram-negative bacteria, especially Pseudomonas aeruginosa, and bacteria which have a lactamase. However, very few penicillin compounds exhibit satisfactory antibacterial activity against said bacteria. For example, resembled compounds of this invention are disclosed in Journal of Antibiotics, Vol. 32, No. 6, page 621 (1979), but do not exhibit satisfactory antibacterial activity against said bacteria.